hi let's talk about your esophagus or the intended pathway for food to proceed through
to the digestive system the esophagus is a fiber a muscular tube that's going to
connect the pharynx to the stomach it's going to move through the neck and the thorax down
into the abdomen now generally we would divide the esophagus into cervical portions in the neck
thoracic portions and the thorax and a tiny little abdominal portion in the abdomen but it might be
easier functionally to think of the esophagus as an upper third and a lower two-thirds that
upper third of the esophagus and that would be the cervical portion of the esophagus located there is
unique in that it consists of largely striated or skeletal muscle the striated muscle though
is not voluntary it's it's under the control of the autonomic nervous system and it's going to
activate during swallowing or the deglutition reflex this upper third is innervated by the
recurrent laryngeal nerves which are branches of the vagus nerve and they're supplied by blood by
the inferior thyroid artery now beyond that upper third the lower two-thirds of the esophagus are
really imbued with smooth muscle and that smooth muscle is under control of the esophageal plexus
the esophageal plexus consists of contributions from the vagal trunk and various branches of the
thoracic sympathetic trunk and this portion of the esophagus is supplied by blood via the esophageal
arteries and other branches such as the left gastric artery and the left inferior phrenic
artery so anatomically there are three portions to the esophagus there's the cervical part of
the esophagus which is going to conduct materials or a bolus down through the neck and then there's
the thoracic part of the esophagus that begins at the root of the neck and is then going to extend
down to the diaphragm and it's going to pierce the diaphragm at the esophageal hiatus which
at rest is approximately at the level of t10 or the 10th thoracic vertebra and then there's the
abdominal portion of the esophagus which is beyond the diaphragm and is adjacent to the cardia of the
stomach now let's take a look at each part of the esophagus in greater detail so here we're
looking at a posterior view of the pharynx and you can see that here as it transitions
into the cervical part of the esophagus here that cervical part of the esophagus is largely striated
or skeletal muscle that's under control of the recurrent laryngeal nerves which are branches
of the vagus here we can see the the first part of the subclavian artery giving rise to the thoracic
trunk the thoracic trunk has a branch called the inferior thyroid artery and those inferior
thyroid arteries are going to send branches out to supply the cervical esophagus with blood the
thoracic esophagus is going to conduct those Boli of food down or across the superior mediastinum
and then the posterior mediastinum and it's going to be nestled between the thoracic part
of the descending aorta which we can see here and the inferior vena cava which would be here but is
been removed in this particular dissection now the esophageal plexus that controls the
thoracic portion of the esophagus consists of contributions of the anterior vagal trunk the
anterior vagal trunk gets most of its supply from the left vagus nerve it also has some
branches from the right so we can see the the left vagus nerve coming down here and supplying
the anterior esophageal plexus but there also a couple of branches descending from the right
there's also a posterior vagal trunk that is predominantly from the the right vagus nerve
and also has some branches from the left now we can see some of those portions of the esophageal
plexus showing up as fine-scale branches just on this anterior portion of the esophagus in
terms of blood flow the thoracic portion of the esophagus gets branches from the thoracic part
of the descending aorta or the thoracic aorta here so there are esophageal arteries now this
part of the esophagus ends at t10 as it is transmitted through the esophageal hiatus of
the diaphragm the final and smallest or shortest part of the esophagus is the abdominal part and
we can see the abdominal part of the esophagus here deviating left into the stomach which we
can see here it is contiguous with the cardia or the cardiac region of the stomach and we can
see the anterior vagal trunk there and this abdominal part of the esophagus continues to
receive innervation from the vagal Trunks and it gets its blood flow largely from the left
inferior phrenic artery the left gastric artery and any continuations of esophageal arteries from
the thorax so materials and at this point we would refer to them as boli singular bolus are
conducted from the esophagus into the stomach and it's here that we're going to have quite a bit of
intensive chemical digestion and we're going to begin the processes of absorption thank you